Numbers Uniquely Bias Spatial Attention: A Novel Paradigm for Understanding Spatial-Numerical Associations

Over the past two-and-a-half decades, numerous empirical studies have demonstrated a relationship between numbers and space. A classic interpretation is that these spatialnumerical associations (SNAs) are a product of a stable mental number line (MNL) in the mind, yet others have argued that SNAs are a product of transient mappings that occur in working memory. Importantly, although the latter interpretation has no implications for the representation of number, the former suggests that the representation of number is inherently spatial. Here, we tease apart questions of spatial representation (à la an MNL perspective) and spatial strategy (à la alternative accounts). In a novel placethe-number task, we demonstrate that numbers automatically bias spatial attention whereas other ordinal sequences (i.e., letters) do not. We argue that this is evidence of an inherently spatial representation of number and explore how this work may help answer future questions about the relationship between space and number.